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An
earthquake An earthquake (also known as a quake, tremor or temblor) is the shaking of the surface of the Earth resulting from a sudden release of energy in the Earth's lithosphere that creates seismic waves. Earthquakes can range in intensity, fr ...
and a
tsunami A tsunami ( ; from ja, 津波, lit=harbour wave, ) is a series of waves in a water body caused by the displacement of a large volume of water, generally in an ocean or a large lake. Earthquakes, volcanic eruptions and other underwater exp ...
, known as the Boxing Day Tsunami and, by the scientific community, the Sumatra–Andaman earthquake, occurred at 07:58:53 local time (
UTC+7 UTC+07:00 is an identifier for a time offset from UTC of +07:00. In ISO 8601 the associated time would be written as . It is 7 hours ahead of UTC, meaning that when the time in UTC areas is midnight (00:00), the time in UTC+07:00 areas would ...
) on 26 December 2004, with an
epicentre The epicenter, epicentre () or epicentrum in seismology is the point on the Earth's surface directly above a hypocenter or focus, the point where an earthquake or an underground explosion originates. Surface damage Before the instrumental pe ...
off the west coast of northern Sumatra,
Indonesia Indonesia, officially the Republic of Indonesia, is a country in Southeast Asia and Oceania between the Indian and Pacific oceans. It consists of over 17,000 islands, including Sumatra, Java, Sulawesi, and parts of Borneo and New Guine ...
. It was an
undersea The underwater environment is the region below the surface of, and immersed in, liquid water in a natural or artificial feature (called a body of water), such as an ocean, sea, lake, pond, reservoir, river, canal, or aquifer. Some characterist ...
megathrust earthquake Megathrust earthquakes occur at convergent plate boundaries, where one tectonic plate is forced underneath another. The earthquakes are caused by slip along the thrust fault that forms the contact between the two plates. These interplate earthqu ...
that registered a magnitude of 9.1–9.3 , reaching a
Mercalli intensity The Modified Mercalli intensity scale (MM, MMI, or MCS), developed from Giuseppe Mercalli's Mercalli intensity scale of 1902, is a seismic intensity scale used for measuring the intensity of shaking produced by an earthquake. It measures the eff ...
up to IX in certain areas. The earthquake was caused by a rupture along the fault between the
Burma Plate The Burma Plate is a minor tectonic plate or microplate located in Southeast Asia, sometimes considered a part of the larger Eurasian Plate. The Andaman Islands, Nicobar Islands, and northwestern Sumatra are located on the plate. This island arc ...
and the Indian Plate. A series of massive
tsunami A tsunami ( ; from ja, 津波, lit=harbour wave, ) is a series of waves in a water body caused by the displacement of a large volume of water, generally in an ocean or a large lake. Earthquakes, volcanic eruptions and other underwater exp ...
waves grew up to high once heading inland, after being created by the underwater seismic activity offshore. Communities along the surrounding coasts of the Indian Ocean were devastated, and the tsunamis killed an estimated 227,898 people in 14 countries, making it one of the deadliest natural disasters in recorded history. The direct results caused major disruptions to living conditions and commerce in coastal provinces of surrounded countries, including Aceh (Indonesia), Sri Lanka,
Tamil Nadu Tamil Nadu (; , TN) is a state in southern India. It is the tenth largest Indian state by area and the sixth largest by population. Its capital and largest city is Chennai. Tamil Nadu is the home of the Tamil people, whose Tamil language ...
(
India India, officially the Republic of India (Hindi: ), is a country in South Asia. It is the seventh-largest country by area, the second-most populous country, and the most populous democracy in the world. Bounded by the Indian Ocean on the so ...
) and Khao Lak (Thailand). Banda Aceh reported the largest number of deaths. The earthquake was the third-largest ever recorded, the largest in the 21st century and had the longest duration of
faulting In geology, a fault is a planar fracture or discontinuity in a volume of rock across which there has been significant displacement as a result of rock-mass movements. Large faults within Earth's crust result from the action of plate tectonic ...
ever observed, between eight and ten minutes. It caused the planet to vibrate as much as , and also
remotely triggered earthquakes Remotely triggered earthquakes are a result of the effects of large earthquakes at considerable distance, outside of the immediate aftershock zone. The farther one gets from the initiating earthquake in both space and time, the more difficult it is ...
as far away as
Alaska Alaska ( ; russian: Аляска, Alyaska; ale, Alax̂sxax̂; ; ems, Alas'kaaq; Yup'ik: ''Alaskaq''; tli, Anáaski) is a state located in the Western United States on the northwest extremity of North America. A semi-exclave of the U.S. ...
. Its epicentre was between
Simeulue Simeulue is an island of Indonesia, off the west coast of Sumatra. It covers an area of 1754 square kilometres (677 square miles), including minor offshore islands. It had a population of 80,674 at the 2010 census and 92,865 at the 2020 census ...
and mainland Sumatra. The plight of the affected people and countries prompted a worldwide
humanitarian response Humanitarian aid is material and logistic assistance to people who need help. It is usually short-term help until the long-term help by the government and other institutions replaces it. Among the people in need are the homeless, refugees, and v ...
, with donations totalling more than US$14 billion.


Earthquake

The 2004 Indian Ocean earthquake was initially documented as having a
moment magnitude The moment magnitude scale (MMS; denoted explicitly with or Mw, and generally implied with use of a single M for magnitude) is a measure of an earthquake's magnitude ("size" or strength) based on its seismic moment. It was defined in a 1979 pape ...
of 8.8. In February 2005, scientists revised the estimate of the magnitude to 9.0. Although the
Pacific Tsunami Warning Center The Pacific Tsunami Warning Center (PTWC) is one of two tsunami warning centers that are operated by NOAA in the United States. Headquartered on Ford Island, HI, the PTWC is part of an international tsunami warning system (TWS) program and s ...
has accepted these new numbers, the
United States Geological Survey The United States Geological Survey (USGS), formerly simply known as the Geological Survey, is a scientific agency of the United States government. The scientists of the USGS study the landscape of the United States, its natural resources, ...
has, as of 2022, so far not changed its estimate of 9.1. A 2006 study estimated a magnitude of 9.1–9.3;
Hiroo Kanamori is a Japanese seismologist who has made fundamental contributions to understanding the physics of earthquakes and the tectonic processes that cause them. Career Kanamori and American seismologist Thomas C. Hanks developed the moment magnitud ...
of the
California Institute of Technology The California Institute of Technology (branded as Caltech or CIT)The university itself only spells its short form as "Caltech"; the institution considers other spellings such a"Cal Tech" and "CalTech" incorrect. The institute is also occasional ...
estimates that 9.2 is representative of the earthquake's size. The
hypocentre In seismology, a hypocenter or hypocentre () is the point of origin of an earthquake or a subsurface nuclear explosion. A synonym is the focus of an earthquake. Earthquakes An earthquake's hypocenter is the position where the strain energy s ...
of the main earthquake was approximately off the western coast of northern Sumatra, in the Indian Ocean just north of
Simeulue Simeulue is an island of Indonesia, off the west coast of Sumatra. It covers an area of 1754 square kilometres (677 square miles), including minor offshore islands. It had a population of 80,674 at the 2010 census and 92,865 at the 2020 census ...
island at a depth of below mean sea level (initially reported as ). The northern section of the Sunda megathrust ruptured over a length of . The earthquake (followed by the tsunami) was felt in
Bangladesh Bangladesh (}, ), officially the People's Republic of Bangladesh, is a country in South Asia. It is the eighth-most populous country in the world, with a population exceeding 165 million people in an area of . Bangladesh is among the mos ...
,
India India, officially the Republic of India (Hindi: ), is a country in South Asia. It is the seventh-largest country by area, the second-most populous country, and the most populous democracy in the world. Bounded by the Indian Ocean on the so ...
,
Malaysia Malaysia ( ; ) is a country in Southeast Asia. The federation, federal constitutional monarchy consists of States and federal territories of Malaysia, thirteen states and three federal territories, separated by the South China Sea into two r ...
,
Myanmar Myanmar, ; UK pronunciations: US pronunciations incl. . Note: Wikipedia's IPA conventions require indicating /r/ even in British English although only some British English speakers pronounce r at the end of syllables. As John Wells explai ...
, Thailand, Sri Lanka and the Maldives. Splay faults, or secondary "pop up faults", caused long, narrow parts of the seafloor to pop up in seconds. This quickly elevated the height and increased the speed of waves, destroying the nearby Indonesian town of Lhoknga. Indonesia lies between the Pacific Ring of Fire along the north-eastern islands adjacent to
New Guinea New Guinea (; Hiri Motu: ''Niu Gini''; id, Papua, or , historically ) is the world's second-largest island with an area of . Located in Oceania in the southwestern Pacific Ocean, the island is separated from Australia by the wide Torr ...
, and the
Alpide belt The Alpide belt or Alpine-Himalayan orogenic belt,K.M. Storetvedt, K. M., ''The Tethys Sea and the Alpine-Himalayan orogenic belt; mega-elements in a new global tectonic system,'' Physics of the Earth and Planetary Interiors, Volume 62, Issues 1 ...
that runs along the south and west from Sumatra, Java, Bali, Flores to Timor. The 2002 Sumatra earthquake is believed to have been a
foreshock A foreshock is an earthquake that occurs before a larger seismic event (the mainshock) and is related to it in both time and space. The designation of an earthquake as ''foreshock'', ''mainshock'' or aftershock is only possible after the full se ...
, preceding the main event by over two years.


Historical comparisons

Great earthquakes, such as the 2004 Indian Ocean earthquake, are associated with megathrust events in subduction zones. Their
seismic moment Seismic moment is a quantity used by seismologists to measure the size of an earthquake. The scalar seismic moment M_0 is defined by the equation M_0=\mu AD, where *\mu is the shear modulus of the rocks involved in the earthquake (in pascals (Pa), ...
s can account for a significant fraction of the global seismic moment across century-scale periods. Of all the moment released by earthquakes in the 100 years from 1906 through 2005, roughly one eighth was due to the 2004 Indian Ocean earthquake. This quake, together with the Great Alaskan earthquake (1964) and the
Great Chilean earthquake The 1960 Valdivia earthquake and tsunami ( es, link=no, Terremoto de Valdivia) or the Great Chilean earthquake (''Gran terremoto de Chile'') on 22 May 1960 was the most powerful earthquake ever recorded. Various studies have placed it at 9.4– ...
(1960), account for almost half of the total moment. Since 1900, the only earthquakes recorded with a greater magnitude were the
1960 Valdivia earthquake The 1960 Valdivia earthquake and tsunami ( es, link=no, Terremoto de Valdivia) or the Great Chilean earthquake (''Gran terremoto de Chile'') on 22 May 1960 was the most powerful earthquake ever recorded. Various studies have placed it at 9.4– ...
(magnitude 9.5) and the 1964 Alaska earthquake in Prince William Sound (magnitude 9.2). The only other recorded earthquakes of magnitude 9.0 or greater were off
Kamchatka The Kamchatka Peninsula (russian: полуостров Камчатка, Poluostrov Kamchatka, ) is a peninsula in the Russian Far East, with an area of about . The Pacific Ocean and the Sea of Okhotsk make up the peninsula's eastern and west ...
, Russia, on 4 November 1952 (magnitude 9.0) and Tōhoku, Japan (magnitude 9.1) in March 2011. Each of these megathrust earthquakes also spawned tsunamis in the Pacific Ocean. In comparison to the 2004 Indian Ocean earthquake, the death toll from these earthquakes and tsunamis was significantly lower, primarily because of the lower population density along the coasts near affected areas. Other huge megathrust earthquakes occurred in 1868 (Peru, Nazca Plate and South American Plate); 1827 (Colombia, Nazca Plate and South American Plate); 1812 (Venezuela, Caribbean Plate and South American Plate) and
1700 As of March 1 ( O.S. February 19), where then Julian calendar acknowledged a leap day and the Gregorian calendar did not, the Julian calendar fell one day further behind, bringing the difference to 11 days until February 28 ( O.S. February 17 ...
(western North America, Juan de Fuca Plate and North American Plate). All of them are believed to be greater than magnitude 9, but no accurate measurements were available at the time.


Tectonic plates

The 2004 Indian Ocean earthquake was unusually large in geographical and geological extent. An estimated of fault surface slipped (or ruptured) about along the subduction zone where the Indian Plate slides (or subducts) under the overriding Burma Plate. The slip did not happen instantaneously but took place in two phases over several minutes: Seismographic and acoustic data indicate that the first phase involved a rupture about long and wide, beneath the sea bed—the largest rupture ever known to have been caused by an earthquake. The rupture proceeded at about , beginning off the coast of Aceh and proceeding north-westerly over about 100 seconds. After a pause of about another 100 seconds, the rupture continued northwards towards the Andaman and Nicobar Islands. The northern rupture occurred more slowly than in the south, at about , continuing north for another five minutes to a plate boundary where the fault type changes from subduction to strike-slip (the two plates slide past one another in opposite directions). The Indian Plate is part of the great Indo-Australian Plate, which underlies the Indian Ocean and Bay of Bengal, and is moving north-east at an average of . The India Plate meets the
Burma Plate The Burma Plate is a minor tectonic plate or microplate located in Southeast Asia, sometimes considered a part of the larger Eurasian Plate. The Andaman Islands, Nicobar Islands, and northwestern Sumatra are located on the plate. This island arc ...
(which is considered a portion of the great Eurasian Plate) at the
Sunda Trench The Sunda Trench, earlier known as and sometimes still indicated as the Java Trench, is an oceanic trench located in the Indian Ocean near Sumatra, formed where the Australian- Capricorn plates subduct under a part of the Eurasian Plate. It is ...
. At this point, the India Plate subducts beneath the Burma Plate, which carries the Nicobar Islands, the Andaman Islands, and northern Sumatra. The India Plate sinks deeper and deeper beneath the Burma Plate until the increasing temperature and pressure drive volatiles out of the subducting plate. These volatiles rise into the overlying plate, causing partial melting and the formation of magma. The rising magma intrudes into the crust above and exits the Earth's crust through volcanoes in the form of a volcanic arc. The volcanic activity that results as the Indo-Australian Plate subducts the Eurasian Plate has created the Sunda Arc. As well as the sideways movement between the plates, the 2004 Indian Ocean earthquake resulted in a rise of the seafloor by several metres, displacing an estimated of water and triggering devastating tsunami waves. The waves radiated outwards along the entire length of the rupture (acting as a line source). This greatly increased the geographical area over which the waves were observed, reaching as far as Mexico, Chile, and the Arctic. The raising of the seafloor significantly reduced the capacity of the Indian Ocean, producing a permanent rise in the global sea level by an estimated .


Aftershocks and other earthquakes

Numerous aftershocks were reported off the Andaman Islands, the Nicobar Islands and the region of the original epicentre in the hours and days that followed. The magnitude 8.7 2005 Nias–Simeulue earthquake, which originated off the coast of the Sumatran island of Nias, is not considered an aftershock, despite its proximity to the epicentre, and was most likely triggered by stress changes associated with the 2004 event. The earthquake produced its own aftershocks (some registering a magnitude of as high as 6.1) and presently ranks as the third-largest earthquake ever recorded on the moment magnitude or Richter magnitude scale. Other aftershocks of up to magnitude 6.6 continued to shake the region daily for three or four months. As well as continuing aftershocks, the energy released by the original earthquake continued to make its presence felt well after the event. A week after the earthquake, its reverberations could still be measured, providing valuable scientific data about the Earth's interior. The 2004 Indian Ocean earthquake came just three days after a magnitude 8.1 earthquake in the sub-antarctic
Auckland Islands The Auckland Islands (Māori: ''Motu Maha'' "Many islands" or ''Maungahuka'' "Snowy mountains") are an archipelago of New Zealand, lying south of the South Island. The main Auckland Island, occupying , is surrounded by smaller Adams Islan ...
, an uninhabited region west of New Zealand, and
Macquarie Island Macquarie Island is an island in the southwestern Pacific Ocean, about halfway between New Zealand and Antarctica. Regionally part of Oceania and politically a part of Tasmania, Australia, since 1900, it became a Tasmanian State Reserve in 197 ...
to Australia's north. This is unusual since earthquakes of magnitude eight or more occur only about once per year on average. The
U.S. Geological Survey The United States Geological Survey (USGS), formerly simply known as the Geological Survey, is a scientific agency of the United States government. The scientists of the USGS study the landscape of the United States, its natural resources, and ...
sees no evidence of a causal relationship between these events. The 2004 Indian Ocean earthquake is thought to have triggered activity in both Leuser Mountain and Mount Talang, volcanoes in Aceh along the same range of peaks, while the 2005 Nias–Simeulue earthquake had sparked activity in Lake Toba, an ancient crater in Sumatra.


Energy released

The energy released on the Earth's surface (''M''E, which is the ''seismic potential for damage'') by the 2004 Indian Ocean earthquake was estimated at . This energy is equivalent to over 1,500 times that of the Hiroshima atomic bomb, but less than that of Tsar Bomba, the largest nuclear weapon ever detonated. The earthquake generated a seismic oscillation of the Earth's surface of up to , equivalent to the effect of the
tidal forces The tidal force is a gravitational effect that stretches a body along the line towards the center of mass of another body due to a gradient (difference in strength) in gravitational field from the other body; it is responsible for diverse phenomen ...
caused by the Sun and Moon. The seismic waves of the earthquake were felt across the planet, as far away as the U.S. state of Oklahoma, where vertical movements of were recorded. By February 2005, the earthquake's effects were still detectable as a complex harmonic oscillation of the Earth's surface, which gradually diminished and merged with the incessant free oscillation of the Earth more than four months after the earthquake. Because of its enormous energy release and shallow rupture depth, the earthquake generated remarkable seismic ground motions around the globe, particularly due to huge Rayleigh (surface) elastic waves that exceeded in vertical amplitude everywhere on Earth. The record section plot displays vertical displacements of the Earth's surface recorded by seismometers from the IRIS/USGS Global Seismographic Network plotted with respect to time (since the earthquake initiation) on the horizontal axis, and vertical displacements of the Earth on the vertical axis (note the 1 cm scale bar at the bottom for scale). The seismograms are arranged vertically by distance from the epicentre in degrees. The earliest, lower amplitude signal is that of the compressional (P) wave, which takes about 22 minutes to reach the other side of the planet (the antipode; in this case near Ecuador). The largest amplitude signals are seismic surface waves that reach the antipode after about 100 minutes. The surface waves can be clearly seen to reinforce near the antipode (with the closest seismic stations in Ecuador), and to subsequently encircle the planet to return to the epicentral region after about 200 minutes. A major aftershock (magnitude 7.1) can be seen at the closest stations starting just after the 200-minute mark. The aftershock would be considered a major earthquake under ordinary circumstances but is dwarfed by the mainshock. The shift of mass and the massive release of energy slightly altered the Earth's rotation. Weeks after the earthquake, theoretical models suggested the earthquake shortened the length of a day by 2.68
microseconds A microsecond is a unit of time in the International System of Units (SI) equal to one millionth (0.000001 or 10−6 or ) of a second. Its symbol is μs, sometimes simplified to us when Unicode is not available. A microsecond is equal to 1000 ...
, due to a decrease in the oblateness of the Earth. It also caused the Earth to minutely "wobble" on its axis by up to in the direction of 145° east
longitude Longitude (, ) is a geographic coordinate that specifies the east– west position of a point on the surface of the Earth, or another celestial body. It is an angular measurement, usually expressed in degrees and denoted by the Greek lette ...
, or perhaps by up to . Because of tidal effects of the Moon, the length of a day increases at an average of 15 microseconds per year, so any rotational change due to the earthquake will be lost quickly. Similarly, the natural
Chandler wobble The Chandler wobble or Chandler variation of latitude is a small deviation in the Earth's axis of rotation relative to the solid earth, which was discovered by and named after American astronomer Seth Carlo Chandler in 1891. It amounts to change o ...
of the Earth, which in some cases can be up to , will eventually offset the minor wobble produced by the earthquake. There was movement laterally and vertically along the fault line. Early speculation was that some of the smaller islands south-west of Sumatra, which is on the
Burma Plate The Burma Plate is a minor tectonic plate or microplate located in Southeast Asia, sometimes considered a part of the larger Eurasian Plate. The Andaman Islands, Nicobar Islands, and northwestern Sumatra are located on the plate. This island arc ...
(the southern regions are on the Sunda Plate), might have moved south-west by up to , but more accurate data released more than a month after the earthquake found the movement to be about . Since movement was vertical as well as lateral, some coastal areas may have been moved to below sea level. The Andaman and Nicobar Islands appear to have shifted south-west by around and to have sunk by . In February 2005, the
Royal Navy The Royal Navy (RN) is the United Kingdom's naval warfare force. Although warships were used by English and Scottish kings from the early medieval period, the first major maritime engagements were fought in the Hundred Years' War against ...
vessel surveyed the seabed around the earthquake zone, which varies in depth between . The survey, conducted using a high-resolution, multi-beam sonar system, revealed that the earthquake had made a considerable impact on the topography of the seabed. thrust ridges created by previous geologic activity along the fault had collapsed, generating landslides several kilometres wide. One such landslide consisted of a single block of rock some high and long. The momentum of the water displaced by tectonic uplift had also dragged massive slabs of rock, each weighing millions of tonnes, as far as across the seabed. An
oceanic trench Oceanic trenches are prominent long, narrow topographic depressions of the ocean floor. They are typically wide and below the level of the surrounding oceanic floor, but can be thousands of kilometers in length. There are about of oceanic tren ...
several kilometres wide was exposed in the earthquake zone. The TOPEX/Poseidon and Jason-1 satellites happened to pass over the tsunami as it was crossing the ocean. These satellites carry radars that measure precisely the height of the water surface; anomalies in the order of were measured. Measurements from these satellites may prove invaluable for the understanding of the earthquake and tsunami. Unlike data from
tide gauge A tide gauge is a device for measuring the change in sea level relative to a vertical datum. It its also known as mareograph, marigraph, sea-level recorder and limnimeter. When applied to freshwater continental water bodies, the instrument ma ...
s installed on shores, measurements obtained in the middle of the ocean can be used for computing the parameters of the source earthquake without having to compensate for the complex ways in which proximity to the coast changes the size and shape of a wave.


Tsunami

The sudden vertical rise of the seabed by several metres during the earthquake displaced massive volumes of water, resulting in a tsunami that struck the coasts of the Indian Ocean. A tsunami that causes damage far away from its source is sometimes called a teletsunami and is much more likely to be produced by the vertical motion of the seabed than by horizontal motion. The tsunami, like all others, behaved differently in deep water than in shallow water. In deep ocean water, tsunami waves form only a low, broad hump, barely noticeable and harmless, which generally travels at high speed of ; in shallow water near coastlines, a tsunami slows down to only tens of kilometres per hour but, in doing so, forms large destructive waves. Scientists investigating the damage in Aceh found evidence that the wave reached a height of when coming ashore along large stretches of the coastline, rising to in some areas when travelling inland. Radar satellites recorded the heights of tsunami waves in deep water: maximum height was at two hours after the earthquake, the first such observations ever made. According to Tad Murty, vice-president of the Tsunami Society, the total energy of the tsunami waves was equivalent to about , which is more than twice the total explosive energy used during all of World War II (including the two atomic bombs) but still a couple of
orders of magnitude An order of magnitude is an approximation of the logarithm of a value relative to some contextually understood reference value, usually 10, interpreted as the base of the logarithm and the representative of values of magnitude one. Logarithmic dis ...
less than the energy released in the earthquake itself. In many places, the waves reached as far as inland. Because the fault affected by the earthquake was in a nearly north–south orientation, the greatest strength of the tsunami waves was in an east–west direction.
Bangladesh Bangladesh (}, ), officially the People's Republic of Bangladesh, is a country in South Asia. It is the eighth-most populous country in the world, with a population exceeding 165 million people in an area of . Bangladesh is among the mos ...
, which lies at the northern end of the Bay of Bengal, had few casualties despite being a low-lying country relatively near the epicentre. It also benefited from the fact that the earthquake proceeded more slowly in the northern rupture zone, greatly reducing the energy of the water displacements in that region. Coasts that have a landmass between them and the tsunami's location of origin are usually safe; however, tsunami waves can sometimes
diffract Diffraction is defined as the interference or bending of waves around the corners of an obstacle or through an aperture into the region of geometrical shadow of the obstacle/aperture. The diffracting object or aperture effectively becomes a s ...
around such landmasses. Thus, the state of
Kerala Kerala ( ; ) is a state on the Malabar Coast of India. It was formed on 1 November 1956, following the passage of the States Reorganisation Act, by combining Malayalam-speaking regions of the erstwhile regions of Cochin, Malabar, South ...
was hit by the tsunami despite being on the western coast of India, and the western coast of Sri Lanka suffered substantial impacts. Distance alone was no guarantee of safety, as Somalia was hit harder than Bangladesh despite being much farther away. Because of the distances involved, the tsunami took anywhere from fifteen minutes to seven hours to reach the coastlines. The northern regions of the Indonesian island of Sumatra were hit quickly, while Sri Lanka and the east coast of India were hit roughly 90 minutes to two hours later. Thailand was struck about two hours later despite being closer to the epicentre because the tsunami travelled more slowly in the shallow Andaman Sea off its western coast. The tsunami was noticed as far as
Struisbaai Struisbaai is a coastal town in the Overberg region of South Africa's Western Cape province. The town is in the Cape Agulhas Local Municipality in the Overberg District, about two hundred kilometres south east of Cape Town, and four kilometres ...
in South Africa, about away, where a tide surged on shore about 16 hours after the earthquake. It took a relatively long time to reach Struisbaai at the southernmost point of Africa, probably because of the broad continental shelf off South Africa and because the tsunami would have followed the South African coast from east to west. The tsunami also reached Antarctica, where tidal gauges at Japan's Showa Base recorded oscillations of up to a metre (), with disturbances lasting a couple of days. Some of the tsunami's energy escaped into the Pacific Ocean, where it produced small but measurable tsunamis along the western coasts of North and South America, typically around . At Manzanillo, Mexico, a crest-to-trough tsunami was measured. As well, the tsunami was large enough to be detected in
Vancouver Vancouver ( ) is a major city in western Canada, located in the Lower Mainland region of British Columbia. As the List of cities in British Columbia, most populous city in the province, the 2021 Canadian census recorded 662,248 people in the ...
, which puzzled many scientists, as the tsunamis measured in some parts of South America were larger than those measured in some parts of the Indian Ocean. It has been theorized that the tsunamis were focused and directed at long ranges by the mid-ocean ridges which run along the margins of the continental plates.


Early signs and warnings

Despite a delay of up to several hours between the earthquake and the impact of the tsunami, nearly all of the victims were taken by surprise. There were no
tsunami warning system A tsunami warning system (TWS) is used to detect tsunamis in advance and issue the warnings to prevent loss of life and damage to property. It is made up of two equally important components: a network of sensors to detect tsunamis and a communica ...
s in the Indian Ocean to detect tsunamis or to warn the general population living around the ocean. Tsunami detection is not easy because while a tsunami is in deep water, it has little height and a network of sensors is needed to detect it. Tsunamis are more frequent in the Pacific Ocean than in other oceans because of earthquakes in the " Ring of Fire". Although the extreme western edge of the Ring of Fire extends into the Indian Ocean (the point where the earthquake struck), no warning system exists in that ocean. Tsunamis there are relatively rare despite earthquakes being relatively frequent in Indonesia. The last major tsunami was caused by the 1883 eruption of Krakatoa. Not every earthquake produces large tsunamis: on 28 March 2005, a magnitude 8.7 earthquake hit roughly the same area of the Indian Ocean but did not result in a major tsunami. The first warning sign of a possible tsunami is the earthquake itself. However, tsunamis can strike thousands of kilometres away where the earthquake is felt only weakly or not at all. Also, in the minutes preceding a tsunami strike, the sea sometimes recedes temporarily from the coast, which was observed on the eastern earthquake rupture zone such as the coastlines of Aceh, Phuket island, and Khao Lak area in Thailand, Penang island of Malaysia, and the Andaman and Nicobar islands. This rare sight reportedly induced people, especially children, to visit the coast to investigate and collect stranded fish on as much as of exposed beach, with fatal results. However, not all tsunamis cause this "disappearing sea" effect. In some cases, there are no warning signs at all: the sea will suddenly swell without retreating, surprising many people and giving them little time to flee. One of the few coastal areas to evacuate ahead of the tsunami was on the Indonesian island of
Simeulue Simeulue is an island of Indonesia, off the west coast of Sumatra. It covers an area of 1754 square kilometres (677 square miles), including minor offshore islands. It had a population of 80,674 at the 2010 census and 92,865 at the 2020 census ...
, close to the epicentre. Island folklore recounted an earthquake and tsunami in 1907, and the islanders fled to inland hills after the initial shaking and before the tsunami struck. These tales and oral folklore from previous generations may have helped the survival of the inhabitants. On Maikhao Beach in north Phuket City, Thailand, a 10-year-old British tourist named Tilly Smith had studied tsunamis in geography at school and recognised the warning signs of the receding ocean and frothing bubbles. She and her parents warned others on the beach, which was evacuated safely. John Chroston, a biology teacher from Scotland, also recognised the signs at Kamala Bay north of Phuket, taking a busload of vacationers and locals to safety on higher ground. Anthropologists had initially expected the aboriginal population of the Andaman Islands to be badly affected by the tsunami and even feared the already depopulated Onge tribe could have been wiped out. Many of the aboriginal tribes evacuated and suffered fewer casualties, however. Oral traditions developed from previous earthquakes helped the aboriginal tribes escape the tsunami. For example, the folklore of the Onges talks of "huge shaking of ground followed by high wall of water". Almost all of the Onge people seemed to have survived the tsunami.


Indonesia


Aceh

The tsunami devastated the coastline of Aceh province, about 20 minutes after the earthquake. Banda Aceh, the closest major city, suffered severe casualties. The sea receded and exposed the seabed, prompting locals to collect stranded fish and explore the area. Local eyewitnesses described three large waves, with the first wave rising gently to the foundation of the buildings, followed minutes later by a sudden withdrawal of the sea near the port of Ulee Lheue. This was succeeded by the appearance of two large black-coloured steep waves which then travelled inland into the capital city as a large turbulent bore. Eyewitnesses described the tsunami as a "black giant", "mountain" and a "wall of water". Video footage revealed torrents of black water, surging by windows of a two-story residential area situated about inland. Additionally, amateur footage recorded in the middle of the city captured an approaching black surge flowing down the city streets, full of debris, inundating them. The level of destruction was extreme on the northwestern areas of the city, immediately inland of the aquaculture ponds, and directly facing the Indian Ocean. The tsunami height was reduced from at Ulee Lheue to a further to the north-east. The inundation was observed to extend inland throughout the city. Within of the shoreline, houses, except for strongly-built reinforced concrete ones with brick walls, which seemed to have been partially damaged by the earthquake before the tsunami attack, were swept away or destroyed by the tsunami. The area toward the sea was wiped clean of nearly every structure, while closer to the river, dense construction in a commercial district showed the effects of severe flooding. The flow depth at the city was just at the level of the second floor, and there were large amounts of debris piled along the streets and in the ground-floor storefronts. In the seaside section of Ulee Lheue, the flow depths were over . Footage showed evidence of back-flowing of the Aceh River, carrying debris and people from destroyed villages at the coast and transporting them up to inland. A group of small islands: Weh, Breueh, Nasi, Teunom, Bunta, Lumpat, and Batee lie just north of the capital city. The tsunami reached a run-up of on the western shorelines of Breueh Island and Nasi Island. Coastal villages were destroyed by the waves. On the island of Pulau Weh, strong surges were experienced in the port of Sabang, yet there was little damage with reported runup values of , most likely due to the island being sheltered from the direct attack by the islands to the south-west. Lhoknga is a small coastal community about south-west of Banda Aceh, located on a flat coastal plain in between two rainforest-covered hills, overlooking a large bay and famous for its large swathe of white sandy beach and surfing activities. The locals reported 10 to 12 waves, with the second and third being the highest and most destructive. Interviews with the locals revealed that the sea temporarily receded and exposed coral reefs. In the distant horizon, gigantic black waves about high made explosion-like sounds as it broke and approached the shore. The first wave came rapidly landward from the south-west as a turbulent bore about high. The second and third waves were high at the coast and appeared like gigantic surfing waves but "taller than the coconut trees and was like a mountain". The second wave was the largest; it came from the west-southwest within five minutes of the first wave. The tsunami stranded cargo ships, barges and destroyed a cement mining facility near the Lampuuk coast, where it reached the fourth level of the building.
Meulaboh Meulaboh ( Jawoë: ملابوه; or ''Moulabouh'') is the capital of West Aceh Regency, Indonesia. Geography Meulaboh is about 245 km southeast of Banda Aceh, the capital of Aceh province. Meulaboh is located in the western part of Sumatr ...
, a remote coastal city, was among the hardest hit by the tsunami. The waves arrived after the sea receded about , followed by an advancing small tsunami. The second and third destructive waves arrived later, which exceeded the height of the coconut trees. The inundation distance is about . Other towns on Aceh's west coast hit by the disaster included Leupung, Lhokruet, Lamno, Patek,
Calang Calang ( Jawoë: چالڠ), the capital of the Aceh Jaya Regency of the special territory (''daerah istimewa'') of Aceh was on the island of Sumatra, Indonesia. It had a population of about 12,000 though it was reported to have ''"vanished comp ...
, and Teunom. Affected or destroyed towns on the region's north and east coast were Pidie Regency, Samalanga, Panteraja, and Lhokseumawe. The high fatality rate in the area was mainly due to lack of preparation of the community towards a tsunami and limited knowledge and education among the population regarding the natural phenomenon. Helicopter surveys showed entire settlements virtually destroyed with destruction within miles inland, and only some mosques left standing. The greatest run-up height of the tsunami was measured at a hill between Lhoknga and Leupung, on the western coast of the northern tip of Sumatra, near Banda Aceh, and reached . The tsunami heights in Sumatra: * on the west coast of Aceh * on the Banda Aceh coast * on the Krueng Raya coast * on the
Sigli Sigli is a town in Aceh province of Indonesia and it is the seat (capital) of Pidie Regency. Sigli is located 112 kilometers to the south of the capital of Aceh province, Banda Aceh. Sport Persatuan Sepakbola Aceh Pidie is the football club f ...
coast * on the north coast of Weh Island directly facing the tsunami source * on the opposite side of the coast of Weh Island facing the tsunami


Sri Lanka

The island country of Sri Lanka, located about from Sumatra, was ravaged by the tsunami around 2 hours after the earthquake. The tsunami first struck the eastern coastline and subsequently refracted around the southern point of Sri Lanka (Dondra Head). The refracted tsunami waves then inundated the southwestern part of Sri Lanka after some of its energy was reflected from impact with the Maldives. In Sri Lanka, the civilian casualties were second only to those in Indonesia, with approximately 35,000 killed. The eastern shores of Sri Lanka were the hardest hit since it faced the epicentre of the earthquake, while the southwestern shores were hit later, but the death toll was just as severe. The southwestern shores are a hotspot for tourists and fishing. The degradation of the natural environment in Sri Lanka contributed to the high death tolls. Approximately 90,000 buildings and many wooden houses were destroyed. The tsunami arrived on the island as a small brown-orange-colored flood. Moments later, the ocean floor was exposed as much as in places, which was followed by massive second and third waves. Amateur video recorded at the city of Galle showed a large deluge flooding the city, carrying debris and sweeping away people while in the coastal resort town of
Beruwala Beruwala ( Sinhala:බේරුවල Tamil: பேருவளை) is a large town in Kalutara District, Western Province, Sri Lanka, governed by an Urban Council. The town covers a total area of approximately and is located on the south-west ...
, the tsunami appeared as a huge brown-orange colored bore which reached the first level of a hotel, causing destruction and taking people unaware. Other videos recorded showed that the tsunami appeared like a flood raging inland. The construction of seawalls and breakwaters reduced the power of waves at some locations. The largest run-up measured was at with inundation distance of in Yala. In Hambantota, run-ups measured with the greatest inundation distance of . Run-up measurements along the Sri Lankan coasts are at . Waves measured on the east coast ranged from at Pottuvill to Batticaloa at in the north-east around
Trincomalee Trincomalee (; ta, திருகோணமலை, translit=Tirukōṇamalai; si, ත්‍රිකුණාමළය, translit= Trikuṇāmaḷaya), also known as Gokanna and Gokarna, is the administrative headquarters of the Trincomalee Dis ...
and in the west coast from Moratuwa to Ambalangoda. Sri Lanka tsunami height survey: * at
Koggala Koggala ( si, කොග්ගල, translit=Koggala; ta, கொக்கலை, translit=Kokkalai) is a small coastal town, situated at the edge of a lagoon on the south coast of Sri Lanka, located in Galle District, Southern Province, Sri Lanka, ...
* at Galle port * around the Galle coast * at Nonagama * at
Weligama Weligama ( si, වැලිගම, ta, வெலிகாமம்) is a town on the south coast of Sri Lanka, located in Matara District, Southern Province, Sri Lanka, governed by an Urban Council. The name ''Weligama'', literally means "sandy v ...
* at Dodundawa * at Ambalangoda * at
Hikkaduwa Hikkaduwa is a small town on the south coast of Sri Lanka located in the Southern Province, about north-west of Galle and south of Colombo. Etymology The name Hikkaduwa is thought to have been derived from the two words ''Sip Kaduwa'', with ...
Fishery Harbour * at Kahawa * at North Beach of
Beruwala Beruwala ( Sinhala:බේරුවල Tamil: பேருவளை) is a large town in Kalutara District, Western Province, Sri Lanka, governed by an Urban Council. The town covers a total area of approximately and is located on the south-west ...
* at Paiyagala A regular passenger train operating between Maradana and Matara was derailed and overturned by the tsunami and claimed at least 1,700 lives, the largest single rail disaster death toll in history. Estimates based on the state of the shoreline and a high-water mark on a nearby building place the tsunami above sea level and higher than the top of the train.


Thailand

The tsunami travelled eastward through the Andaman Sea and hit the south-western coasts of Thailand, about 2 hours after the earthquake. Located about from the epicentre, at the time, the region was popular with tourists because of Christmas. Many of these tourists were caught off-guard by the tsunami, as they had no prior warning. The tsunami hit during
high tide Tides are the rise and fall of sea levels caused by the combined effects of the gravitational forces exerted by the Moon (and to a much lesser extent, the Sun) and are also caused by the Earth and Moon orbiting one another. Tide tables c ...
. Major locations damaged included the western shores of Phuket island, the resort town of Khao Lak in Phang Nga Province, the coastal provinces of
Krabi Krabi ( th, กระบี่, ) is the main town in the province of Krabi (''thesaban mueang'') on the west coast of southern Thailand at the mouth of the Krabi River where it empties in Phang Nga Bay. As of 2020, the town had a population of ...
,
Satun Satun (, , ms, Setul) is a town (''thesaban mueang'') in southern Thailand, capital of the Satun Province. It covers the whole ''tambon'' Phiman of Mueang Satun. Satun lies 985 km south of Bangkok. As of 2005 it has a population of 21,498 ...
, Ranong and Trang and small offshore islands like Ko Racha Yai, the Phi Phi islands, the
Surin Islands The Surin Islands ( th, หมู่เกาะสุรินทร์, ) is an archipelago of five islands in the Andaman Sea, 60 km from the Thai mainland. Administratively, the islands are part of Tambon Ko Phra Thong, Khura Buri Dist ...
and the Similan archipelago. Approximately 8,000 people were killed. Thailand experienced the second largest tsunami run-up. The tsunami heights recorded: * in Khao Lak * along the west coast of Phuket island * along the south coast of Phuket island * along the east coast of Phuket island * on the Phi Phi Islands * at Ban Thung Dap * at Ramson * at Ban Thale Nok * at Hat Praphat (Ranong Coastal Resources Research Station) * at Thai Mueang District * at Rai Dan The province of Phang Nga was the most affected area in Thailand. The quiet resort town of Khao Lak is located on a stretch of golden sandy beach, famed for its hotels overlooking the Andaman Sea and hilly rainforests. A video, taken by a local restaurant manager from a hill adjacent to the beach, showed that the tsunami's arrival was preceded by a sudden retreat of the sea exposing the seafloor. Many tourists and locals can be seen trying to gather fish. Moments later, the tsunami arrives as a wall of foaming water that slams into the coast, washing away numerous people who had no time to escape. Another amateur video, captured by a German family at beach level, showed the tsunami appearing as a white horizontal line in the distant horizon, gradually becoming bigger (bore-like), engulfing a jet skier and lifting two police boats. A maximum inundation of approximately was measured, the inundated depths were and there was evidence that the tsunami reached the third floor of a resort hotel. The tsunami in Khao Lak was bigger due to offshore coral reefs and shallow seafloor which caused the tsunami to pile-up. This was similar to eyewitness accounts of the tsunami at Banda Aceh. Khao Lak also experienced the largest tsunami run-up height outside of Sumatra.. The highest-recorded tsunami run-up was measured at Ban Thung Dap, on the south-west tip of Ko Phra Thong Island and the second-highest at at Ban Nam Kim. Moreover, the largest death toll occurred at Khao Lak, with about 5,000 people killed. In addition, the
tsunami A tsunami ( ; from ja, 津波, lit=harbour wave, ) is a series of waves in a water body caused by the displacement of a large volume of water, generally in an ocean or a large lake. Earthquakes, volcanic eruptions and other underwater exp ...
inflicted damage to the popular resort town of Ao Nang in Krabi Province. Video footage showed that the tsunami appeared as multiple white surfs violently lifting up yachts, boats and crashing onto beaches. Footage captured at Koh Lanta showed a wall of water swamping the beach, while another video taken at another location showed a large surfing wave like tsunami approaching the shore, lifting up a yacht and flooding the beach. At Koh Sriboya, the tsunami advanced inland as a turbulent medium bore, while at Koh Phayam, Ranong Province, the tsunami appeared as a wall of water. At Phuket Province, the island province's western beaches were struck by the tsunami. At Patong Beach, a popular tourist destination, the tsunami first arrived as a small flood, which swept away cars and surprised people. About 10 minutes later, the sea receded for a while before the tsunami arrived again as a large wall of water looming over the skyline and flooding the coast. Another video from Kamala Beach showed the tsunami flooding the ground floor of a restaurant sweeping away an elderly couple. On Karon Beach, Kamala Beach and Kata Beach, the tsunami came in like a surging flood inland carrying people and cars. On some locations, a coastal road was built which was higher than the shore, protecting a hotel which was behind it. On the east coast of Phuket Island, the tsunami height was about 2 m. In one river mouth, many boats were damaged. The tsunami moved counter-clockwise around Phuket Island, as was the case at
Okushiri Island is an island in Hokkaidō, Japan. It has an area of . The town of Okushiri and the Hiyama Prefectural Natural Park encompass the entire island. It has many pastures, beech tree forests, and a rocky coastline. There are two elementary schools, o ...
in the 1993 Hokkaido earthquake. According to interviews, the second wave was the largest. The tsunami heights were and the inundated depth was about . The tsunami surprised many tourists at Koh Racha Yai, where it flooded the resorts. About 250 people perished directly in the tsunami. The
Phi Phi Islands The Phi Phi Islands ( th, หมู่เกาะพีพี, , ) are an island group in Thailand between the large island of Phuket and the Straits of Malacca coast of Thailand. The islands are administratively part of Krabi Province. Ko Phi ...
are a group of small islands that were affected by the tsunami. The north bay of Phi Phi Don Island opens to the north-west in the direction of the tsunami. The measured tsunami height on this beach was . According to eyewitness accounts, the tsunami came from the north and south. The ground level was about 2 m above sea level, where there were many cottages and hotels. The south bay opens to the south-east and faces in the opposite direction from the tsunami. Furthermore, Phi Phi Le Island shields the port of Phi Phi Don Island. The measured tsunami height was in the port. Amateur camcorder footage taken by Israeli tourists showed the tsunami advancing inland suddenly as a small flood, gradually becoming more powerful and engulfing the whole beach and resort, with the tsunami carrying a yacht out to sea. Moreover, the tsunami was detected by scuba divers around offshore islands like the
Similan Islands The Similan Islands ( th, หมู่เกาะสิมิลัน, , , Malay: ''Pulau Sembilan'') is an archipelago in the Andaman Sea off the coast of, and part of, Phang Nga Province in southern Thailand. It is the maritime border bet ...
and the
Surin Islands The Surin Islands ( th, หมู่เกาะสุรินทร์, ) is an archipelago of five islands in the Andaman Sea, 60 km from the Thai mainland. Administratively, the islands are part of Tambon Ko Phra Thong, Khura Buri Dist ...
. The divers reported being caught in a violent, swirling current suddenly while underwater. Local camcorder footage showed the tsunami surging inland and flooding camping equipment at the Similan Islands while the tsunami caught tourists unaware at the Surin Islands, and dragging them out towards the sea.


India

The tsunami reached the states of
Andhra Pradesh Andhra Pradesh (, abbr. AP) is a state in the south-eastern coastal region of India. It is the seventh-largest state by area covering an area of and tenth-most populous state with 49,386,799 inhabitants. It is bordered by Telangana to the ...
and
Tamil Nadu Tamil Nadu (; , TN) is a state in southern India. It is the tenth largest Indian state by area and the sixth largest by population. Its capital and largest city is Chennai. Tamil Nadu is the home of the Tamil people, whose Tamil language ...
along the southeastern coastline of the Indian mainland about 2 hours after the earthquake. At the same time, it arrived in the state of
Kerala Kerala ( ; ) is a state on the Malabar Coast of India. It was formed on 1 November 1956, following the passage of the States Reorganisation Act, by combining Malayalam-speaking regions of the erstwhile regions of Cochin, Malabar, South ...
, on the southwestern coast. There were two to five tsunamis that coincided with the local high tide in some areas. The tsunami runup height measured in mainland India by Ministry of Home Affairs includes: * at Kerala, inundation distance of with of coastline affected * at the southern coastline of Tamil Nadu, inundation distance of with of coastline affected * at the eastern coastline of Tamil Nadu facing tsunami source, inundation distance of with of coastline affected * at Pondicherry, inundation distance of with of coastline affected * at Andhra Pradesh, inundation distance of with of coastline affected Along the coast of
Tamil Nadu Tamil Nadu (; , TN) is a state in southern India. It is the tenth largest Indian state by area and the sixth largest by population. Its capital and largest city is Chennai. Tamil Nadu is the home of the Tamil people, whose Tamil language ...
, the Marina Beach in Chennai was battered by the tsunami which swept across the beach taking morning walkers unaware. Amateur video recorded taken at a resort beach showed the tsunami arriving as a large wall of water as it approached the coast and flooding it as it advanced inland. Besides that, a black muddy tsunami ravaged the city of Karaikal, where 492 people died. The city of Pondicherry, protected by seawalls was relatively unscathed. Local video recorded that before the arrival of the tsunami, people can be seen swarming the beach to check on stranded fish from the exposed beach. Furthermore, at the coastal town of
Kanyakumari Kanniyakumari (; , referring to Devi Kanya Kumari), also known as Cape Comorin, is a city in Kanniyakumari district in the state of Tamil Nadu, India. It is the southern tip of the Indian subcontinent and the southernmost city in mainland Ind ...
, the seabed was exposed briefly before a large wall of water can be seen on the horizon and subsequently flooding the town. Other footage showed the tsunami dramatically crashed into the Vivekananda Rock Memorial. The worst affected area in Tamil Nadu was Nagapattinam district, with 6,051 fatalities caused by a tsunami, followed by Cuddalore district, with many villages destroyed. Most of the people killed were members of the fishing community.
Velankanni Velankanni (''Vēḷāṅkaṇṇi''), is a Special Grade Panchayat Town in Nagapattinam district in the Indian state of Tamil Nadu. It lies on the Coromandel Coast of the Bay of Bengal, 350 km south of Chennai (Madras), 12 km south of ...
a sea shore town with a Catholic
Basilica In Ancient Roman architecture, a basilica is a large public building with multiple functions, typically built alongside the town's Forum (Roman), forum. The basilica was in the Latin West equivalent to a stoa in the Greek East. The building ...
and a popular pilgrimage destination was also one of the worst hit by this tsunami that struck at around 9.30 am on that Sunday, when pilgrims who were mostly from Kerala among others were inside the church attending the
Malayalam Malayalam (; , ) is a Dravidian languages, Dravidian language spoken in the Indian state of Kerala and the union territories of Lakshadweep and Puducherry (union territory), Puducherry (Mahé district) by the Malayali people. It is one of 2 ...
Mass Mass is an intrinsic property of a body. It was traditionally believed to be related to the quantity of matter in a physical body, until the discovery of the atom and particle physics. It was found that different atoms and different eleme ...
. The rising sea water did not enter the shrine, but the receding waters swept away hundreds of pilgrims who were on the beach. The shrine's compound, nearby villages, hundreds of shops, homes and pilgrims were washed away into the sea. About 600 pilgrims died. Rescue teams extricated more than 400 bodies from the sand and rocks in the vicinity and large number of unidentified bodies were buried in mass graves. The state of
Kerala Kerala ( ; ) is a state on the Malabar Coast of India. It was formed on 1 November 1956, following the passage of the States Reorganisation Act, by combining Malayalam-speaking regions of the erstwhile regions of Cochin, Malabar, South ...
experienced tsunami-related damage in three southern densely populated districts, Ernakulam, Alappuzha, and Kollam, due to diffraction of the waves around Sri Lanka. The southernmost district of Thiruvananthapuram, however, escaped damage, possibly due to the wide turn of the diffracted waves at the peninsular tip. Major damage occurred in two narrow strips of land bound on the west by the
Arabian Sea The Arabian Sea ( ar, اَلْبَحرْ ٱلْعَرَبِيُّ, Al-Bahr al-ˁArabī) is a region of the northern Indian Ocean bounded on the north by Pakistan, Iran and the Gulf of Oman, on the west by the Gulf of Aden, Guardafui Channel ...
and on the east by the
Kerala backwaters The Kerala backwaters are a network of brackish lagoons and canals lying parallel to the Arabian Sea of the Malabar coast of Kerala state in south-western India. It also includes interconnected lakes, rivers, and inlets, a labyrinthine system ...
. The waves receded before the first tsunami with the highest fatality reported from the densely populated Alappad panchayat (including the villages of Cheriya Azhikkal and Azhikkal) at Kollam district, caused by a tsunami. A video recorded by locals showed the tsunami flooding the beach and villages, causing despair amongst the villagers. Many villages in the state of
Andhra Pradesh Andhra Pradesh (, abbr. AP) is a state in the south-eastern coastal region of India. It is the seventh-largest state by area covering an area of and tenth-most populous state with 49,386,799 inhabitants. It is bordered by Telangana to the ...
were destroyed. In the Krishna district, the tsunami created havoc in Manginapudi and on Machalipattanam Beach. The most affected was Prakasham District, recording 35 deaths, with maximum damage at Singraikonda. Given the enormous power of the tsunami, the fishing industry suffered the greatest. Moreover, the cost of damage in the transport sector was reported in the tens of thousands. The tsunami run-up was only in areas in the state of Tamil Nadu shielded by the island of Sri Lanka but was in coastal districts such as Nagapattinam in Tamil Nadu directly across from Sumatra. On the western coast, the runup elevations were at Kanyakumari District in Tamil Nadu and each at Kollam and Ernakulam districts in
Kerala Kerala ( ; ) is a state on the Malabar Coast of India. It was formed on 1 November 1956, following the passage of the States Reorganisation Act, by combining Malayalam-speaking regions of the erstwhile regions of Cochin, Malabar, South ...
. The time between the waves ranged from about 15 minutes to 90 minutes. The tsunami varied in height from to based on survivors' accounts. The tsunami travelled at its maximum inland at Karaikal,
Puducherry Puducherry or Pondicherry may refer to: * Puducherry (union territory), a union territory of India ** Pondicherry, capital of the union territory of Puducherry ** Puducherry district, a district of the union territory of Puducherry ** Puducherry t ...
. The
inundation A flood is an overflow of water ( or rarely other fluids) that submerges land that is usually dry. In the sense of "flowing water", the word may also be applied to the inflow of the tide. Floods are an area of study of the discipline hydrolog ...
distance varied between in most areas, except at river mouths, where it was more than . Areas with dense coconut groves or mangroves had much smaller inundation distances, and those with river mouths or backwaters saw larger inundation distances. Presence of seawalls at the Kerala and Tamil Nadu coasts reduced the impact of the waves. However, when the seawalls were made of loose stones, the stones were displaced and carried a few metres inland.


Andaman and Nicobar Islands

Due to close proximity to the earthquake, the tsunami took just minutes to devastate the Andaman and Nicobar Islands. The Andaman Islands were moderately affected while the island of Little Andaman and the Nicobar Islands were severely affected by the tsunami. In South Andaman island, based on local eyewitnesses, there were three tsunami waves, with the third being the most destructive. Flooding occurred at the coast and low-lying areas inland, which were connected to open sea through creeks. Inundation was observed, along the east coast of South Andaman Island, restricted to Chidiyatapu, Burmanallah, Kodiaghat, Beadnabad, Corbyn's cove and Marina Park/Aberdeen Jetty areas. Along the west coast, the inundation was observed around Guptapara, Manjeri, Wandoor, Collinpur and Tirur regions. Several near-shore establishments and numerous infrastructures such as seawalls and a 20 MW diesel-generated power plant at Bamboo Flat were destroyed.T. Ghosh, P. Jana, T.S. Giritharan, S. Bardhan, S.R. Basir, A.K. Ghosh Roy. (2007). Tsunami survey in Andaman and Nicobar group of Islands. Geological Survey of India Special Publication no. 89. 165–184. At
Port Blair Port Blair () is the capital city of the Andaman and Nicobar Islands, a union territory of India in the Bay of Bengal. It is also the local administrative sub-division (''tehsil'') of the islands, the headquarters for the district of South An ...
, the water receded before the first wave, and the third wave was the tallest and caused the most damage. Results of the tsunami survey in South Andaman along Chiriyatapu, Corbyn's Cove and Wandoor beaches: * in maximum tsunami height with a run-up of at Chiriyatapu Beach * in maximum tsunami height and run-up at Corbyn's Cove Beach * in maximum tsunami height and run-up of at Wandoor Beach Meanwhile, in the Little Andaman, tsunami waves impinged on the eastern shore about 25 to 30 minutes after the earthquake in a four-wave cycle of which the fourth tsunami was the most devastating with a wave height of about . The tsunami destroyed settlements at Hut Bay within a range of from the seashore. Run up level up to have been measured. In Malacca, located on the island of
Car Nicobar Car Nicobar ( in Car language) is the northernmost of the Nicobar Islands. It is also one of three local administrative divisions of the Indian district of Nicobar, part of the Indian union territory of Andaman and Nicobar Islands. Annual ra ...
, there were three tsunami waves. The sea was observed to rise suddenly before the onset of the first wave. The first wave came 5 minutes after the earthquake, preceded by a recession of the sea up to .. The second and third waves came in 10 minutes intervals after the first wave. The third wave was the strongest, with a maximum tsunami wave height of . Waves nearly three stories high devastated the Indian Air Force base, located just south of Malacca. The maximum tsunami wave height of . Inundation limit was found to be up to inland. The impact of the waves was so severe that four oil tankers were thrown almost from the seashore near Malacca to the Air force colony main gate. In Chuckchucha and Lapati, the tsunami arrived in a three-wave cycle with a maximum tsunami wave height of . In Campbell Bay of Great Nicobar Island, the tsunami waves hit the area three times with an inundation limit of . A rise in sea level was observed before the first wave came within 5 minutes of the earthquake. The second and third waves came in 10-minute intervals after the first. The second wave was the strongest. The tsunami waves wreaked havoc in the densely populated Jogindar Nagar area, situated south of Campbell Bay. According to local accounts, tsunami waves attacked the area three times. The first wave came five minutes after the mainshock (0629 hrs.) with a marginal drop in sea level. The second wave came 10 minutes after the first one with a maximum height of to 8 m (26 ft) and caused the major destruction. The third wave came within 15 minutes after the second with lower wave height. The maximum inundation limit due to tsunami water was about . The worst affected island in the Andaman & Nicobar chain is Katchall Island, with 303 people confirmed dead and 4,354 missing out of a total population of 5,312. The significant shielding of Port Blair and Campbell Bay by steep mountainous outcrops contributed to the relatively low wave heights at these locations, whereas the open terrain along the eastern coast at Malacca and Hut Bay contributed to the great height of the tsunami waves. Reports of tsunami wave height: * at Diglipur and Rangat at North Andaman Island * high at Campbell Bay on
Great Nicobar Island Great Nicobar is the southernmost and largest of the Nicobar Islands of India, north of Sumatra. History The Nicobar Island has been well known to Indian mariners since the time of the seafaring Cholas https://www.britannica.com/place/Nicobar- ...
* high at Malacca (in Car Nicobar Island) and at Hut Bay on Little Andaman Island * high at Port Blair on South Andaman Island


Maldives

The tsunami severely affected the Maldives at a distance of from the epicentre. Similar to Sri Lanka, survivors reported three waves with the second wave being the most powerful. Being rich in coral reefs, the Maldives provides an opportunity for scientists to assess the impact of a tsunami on coral atolls. The significantly lower tsunami impact on the Maldives compared to Sri Lanka is mostly due to the topography and
bathymetry Bathymetry (; ) is the study of underwater depth of ocean floors (''seabed topography''), lake floors, or river floors. In other words, bathymetry is the underwater equivalent to hypsometry or topography. The first recorded evidence of water ...
of the atoll chain with offshore coral reefs, deep channels separating individual atolls and its arrival within low tide which decreased the power of the tsunami. After the tsunami, there was some concern that the country might be submerged entirely and become uninhabitable. However, this was proven untrue. The highest tsunami wave measured was at Vilufushi Island. The tsunami arrived approximately 2 hours after the earthquake. The greatest tsunami inundation occurred at North Male Atoll, Male island at along the streets. Local footage recorded showed the tsunami flooding the streets up to knee level in town, while another video taken at the beach showed the tsunami slowly flooding and gradually surging inland. The Maldives tsunami wave analysis: * at North Male Atoll, Male Island * at North Male Atoll, Huhule Island * at South Male Atoll, Embudhu Finothu * at Laamu Atoll, Fonadhoo Island * at Laamu Atoll, Gan Island * at North Male Atoll, Dhiffushi Island * at North Male Atoll, Huraa Island * more than at North Male Atoll, Kuda Huraa Island


Myanmar

In
Myanmar Myanmar, ; UK pronunciations: US pronunciations incl. . Note: Wikipedia's IPA conventions require indicating /r/ even in British English although only some British English speakers pronounce r at the end of syllables. As John Wells explai ...
, the tsunami caused only moderate damage, which arrived between 2 and 5.5 hours after the earthquake. Although the country's western Andaman Sea coastline lies at the proximity of the rupture zone, there were smaller tsunamis than the neighbouring Thai coast, because the main tsunami source did not extend to the Andaman Islands. Another factor is that some coasts of Taninthayi Division were protected by the
Myeik Archipelago The Mergui Archipelago (also Myeik Archipelago or ''Myeik Kyunzu''; my, မြိတ်ကျွန်းစု) is located in far southern Myanmar (Burma) and is part of the Tanintharyi Region. It consists of more than 800 islands, varying in ...
. Based on scientific surveys from Ayeyarwaddy Delta through Taninthayi Division, it was revealed that tsunami heights along the Myanmar coast were between . Eyewitnesses compared the tsunami with the "rainy-season high tide"; although at most locations, the tsunami height was similar or smaller than the "rainy-season high tide" level. Tsunami survey heights: * around the Ayeyarwady delta * at Dawei area * around Myeik * around Kawthaung Interviews with local people indicate that they did not feel the earthquake in Taninthayi Division or Ayeyarwaddy Delta. The 71 casualties can be attributed to poor housing infrastructure and additionally, the fact that the coastal residents in the surveyed areas live on flat land along the coast, especially in the Ayeyarwaddy Delta, and that there is no higher ground to which to evacuate. The tsunami heights from the 2004 December earthquake were not more than along the Myanmar coast, the amplitudes were slightly large off the Ayeyarwaddy Delta, probably because the shallow delta caused a concentration in tsunami energy.


Somalia

The tsunami travelled west across the open ocean before striking the East African country of
Somalia Somalia, , Osmanya script: 𐒈𐒝𐒑𐒛𐒐𐒘𐒕𐒖; ar, الصومال, aṣ-Ṣūmāl officially the Federal Republic of SomaliaThe ''Federal Republic of Somalia'' is the country's name per Article 1 of thProvisional Constituti ...
. Around 289 fatalities were reported in the Horn of Africa, drowned by four tsunami waves. The hardest-hit was a stretch of the Somalia coastline between Garacad ( Mudug region) and Xaafuun ( Bari region), which forms part of the
Puntland Puntland ( so, Puntland, ar, أرض البنط, it, Terra di Punt or ''Paese di Punt''), officially the Puntland State of Somalia ( so, Dowlad Goboleedka Puntland ee Soomaaliya, ar, ولاية أرض البنط الصومالية), is a F ...
province. Most of the victims were reported along the low-lying Xaafuun Peninsula. The Puntland coast in northern Somalia was by far the area hardest hit by the waves to the west of the Indian subcontinent. The waves arrived around noon local time. Consequently, tsunami runup heights vary from to with inundation distances varying from to . The maximum runup height of almost was recorded in Bandarbeyla. An even higher runup point was measured on a cliff near the town of Eyl, solely on an eyewitness account. The highest death toll was in
Hafun Hafun ( so, Xaafuun; ar, حافون; grc, Οπώνη, Opṓnē, it, Dante) is a town in the northeastern Bari province of Somalia. Situated in Ras Hafun on the coast of the Guardafui Channel, it is the centre of the Hafun District, and the ea ...
, with 19 dead and 160 people presumed missing out of its 5,000 inhabitants. This was the highest number of casualties in a single African town and the largest tsunami death toll in a single town to the west of the
Indian subcontinent The Indian subcontinent is a list of the physiographic regions of the world, physiographical region in United Nations geoscheme for Asia#Southern Asia, Southern Asia. It is situated on the Indian Plate, projecting southwards into the Indian O ...
. In Xaafuun, small drawbacks were observed before the third and most powerful tsunami wave flooded the town.


Other locations

The tsunami also reached Malaysia, mainly on the northern states such as
Kedah Kedah (), also known by its honorific Darul Aman and historically as Queda, is a state of Malaysia, located in the northwestern part of Peninsular Malaysia. The state covers a total area of over 9,000 km2, and it consists of the mainland ...
, Perak and Penang and on offshore islands such as
Langkawi Langkawi, officially known by its sobriquet Langkawi, the Jewel of Kedah ( ms, Langkawi Permata Kedah ), is a duty-free island and an archipelago of 99 islands (plus five small islands visible only at low tide in the Strait of Malacca) loc ...
island. Peninsular Malaysia was shielded by the full force of the tsunami due to the protection offered by the island of Sumatra, which lies just off the western coast. Bangladesh escaped major damage and deaths because the water displaced by the strike-slip fault was relatively little on the northern section of the rupture zone, which ruptured slowly. In
Yemen Yemen (; ar, ٱلْيَمَن, al-Yaman), officially the Republic of Yemen,, ) is a country in Western Asia. It is situated on the southern end of the Arabian Peninsula, and borders Saudi Arabia to the Saudi Arabia–Yemen border, north and ...
, the tsunami killed two people with a maximum runup of . The tsunami was detected in the southern parts of east Africa, where rough seas were reported, specifically on the eastern and southern coasts that face the Indian Ocean. A few other African countries also recorded fatalities; one in Kenya, three in
Seychelles Seychelles (, ; ), officially the Republic of Seychelles (french: link=no, République des Seychelles; Creole: ''La Repiblik Sesel''), is an archipelagic state consisting of 115 islands in the Indian Ocean. Its capital and largest city, ...
, ten in Tanzania, and South Africa, where two were killed as a direct result of the tsunami—the furthest from the epicentre. Tidal surges also occurred along the
Western Australian Western Australia (commonly abbreviated as WA) is a state of Australia occupying the western percent of the land area of Australia excluding external territories. It is bounded by the Indian Ocean to the north and west, the Southern Ocean to th ...
coast that lasted for several hours, resulting in boats losing their moorings and two people needing to be rescued.


Impact


Countries affected

According to the
U.S. Geological Survey The United States Geological Survey (USGS), formerly simply known as the Geological Survey, is a scientific agency of the United States government. The scientists of the USGS study the landscape of the United States, its natural resources, and ...
, a total of 227,898 people died. Measured in lives lost, this is one of the ten worst earthquakes in recorded history, as well as the single worst tsunami in history. Indonesia was the worst affected area, with most death toll estimates at around 170,000. An initial report by Siti Fadilah Supari, the Indonesian Minister of Health at the time, estimated the death total to be as high as 220,000 in Indonesia alone, giving a total of 280,000 fatalities. However, the estimated number of dead and missing in Indonesia were later reduced by over 50,000. In their report, the Tsunami Evaluation Coalition stated, "It should be remembered that all such data are subject to error, as data on missing persons especially are not always as good as one might wish". A much higher number of deaths has been suggested for Myanmar based on reports from Thailand. The tsunami caused severe damage and deaths as far as the east coast of Africa, with the furthest recorded fatality directly attributed to the tsunami at Rooi-Els, close to
Cape Town Cape Town ( af, Kaapstad; , xh, iKapa) is one of South Africa's three capital cities, serving as the seat of the Parliament of South Africa. It is the legislative capital of the country, the oldest city in the country, and the second largest ...
, from the epicentre. In total, eight people in South Africa died due to high sea levels and waves. Relief agencies reported that one third of the dead appeared to be children. This was a result of the high proportion of children in the populations of many of the affected regions and because children were the least able to resist being overcome by the surging waters. Oxfam went on to report that as many as four times more women than men were killed in some regions because they were waiting on the beach for the fishers to return and looking after their children in the houses. States of emergency were declared in Sri Lanka, Indonesia, and the Maldives. The United Nations estimated at the outset that the relief operation would be the costliest in human history. Then-
UN Secretary-General The secretary-general of the United Nations (UNSG or SG) is the chief administrative officer of the United Nations and head of the United Nations Secretariat, one of the six principal organs of the United Nations. The role of the secretary- ...
Kofi Annan Kofi Atta Annan (; 8 April 193818 August 2018) was a Ghanaian diplomat who served as the seventh secretary-general of the United Nations from 1997 to 2006. Annan and the UN were the co-recipients of the 2001 Nobel Peace Prize. He was the founde ...
stated that reconstruction would probably take between five and ten years. Governments and non-governmental organizations feared that the final death toll might double as a result of diseases, prompting a massive
humanitarian response Humanitarian aid is material and logistic assistance to people who need help. It is usually short-term help until the long-term help by the government and other institutions replaces it. Among the people in need are the homeless, refugees, and v ...
. In addition to a large number of local residents, up to 9,000 foreign tourists (mostly Europeans) enjoying the peak holiday travel season were among the dead or missing, especially people from the Nordic countries. Sweden was the European country most severely affected both in absolute numbers, and by a wide margin when considered in relation to the country's population, with a death toll of 543. Germany was close behind with 539 identified victims.


Environmental impact

Beyond the heavy toll on human lives, the Indian Ocean earthquake has caused an enormous environmental impact that will affect the region for many years to come. It has been reported that severe damage has been inflicted on
ecosystem An ecosystem (or ecological system) consists of all the organisms and the physical environment with which they interact. These biotic and abiotic components are linked together through nutrient cycles and energy flows. Energy enters the syste ...
s such as mangroves, coral reefs, forests, coastal wetlands, vegetation, sand dunes and rock formations, animal and plant
biodiversity Biodiversity or biological diversity is the variety and variability of life on Earth. Biodiversity is a measure of variation at the genetic (''genetic variability''), species (''species diversity''), and ecosystem (''ecosystem diversity'') l ...
and
groundwater Groundwater is the water present beneath Earth's surface in rock and soil pore spaces and in the fractures of rock formations. About 30 percent of all readily available freshwater in the world is groundwater. A unit of rock or an unconsolidated ...
. Also, the spread of solid and liquid waste and industrial chemicals, water pollution and the destruction of sewage collectors and treatment plants threaten the environment even further, in untold ways. The environmental impact will take a long time and significant resources to assess. According to specialists, the main effect is being caused by poisoning of the freshwater supplies and of the soil by saltwater infiltration and a deposit of a salt layer over arable land. It has been reported that in the Maldives, 16 to 17 coral reef atolls that were overcome by sea waves are without fresh water and could be rendered uninhabitable for decades. Uncountable wells that served communities were invaded by sea, sand, and earth; and aquifers were invaded through porous rock. On the island's east coast, the tsunami contaminated wells on which many villagers relied for drinking water. The Colombo-based International Water Management Institute monitored the effects of saltwater and concluded that the wells recovered to pre-tsunami drinking water quality one-and-a-half years after the event. The IWMI developed protocols for cleaning wells contaminated by saltwater; these were subsequently officially endorsed by the World Health Organization as part of its series of Emergency Guidelines. Salted-over soil becomes sterile, and it is difficult and costly to restore for agriculture. It also causes the death of plants and important soil micro-organisms. Thousands of rice, mango, and banana plantations in Sri Lanka were destroyed almost entirely and will take years to recover. In addition to other forms of aid, the Australian government sent ecological experts to help develop strategies for reef-monitoring and rehabilitation of marine environments and coral reefs in the Maldives, Seychelles and other areas. Scientists had developed significant ecological expertise from work with the Great Barrier Reef, in Australia's northeastern waters. In response to the unprecedented situation, the United Nations Environment Programme (UNEP) worked with governments in the region to determine the severity of the ecological impact and how to address it. UNEP established an emergency fund, set up a Task Force to respond to requests for assistance from countries affected by the tsunami, and was able to mobilize and distribute approximately US$9.3 million for environmental recovery and disaster risk reduction between 2004 and 2007. Funding came from other international agencies and from countries including Finland, Norway, Spain, Sweden and the United Kingdom. Evidence suggested that the presence of mangroves in coastal areas had provided some protection, when compared to areas that had been cleared for aquaculture or development. As a result,
mangrove restoration Mangrove restoration is the regeneration of mangrove forest ecosystems in areas where they have previously existed. The practice of mangrove restoration is grounded in the discipline of restoration ecology, which aims to “ ssistthe recovery of re ...
become a focus of a number of projects, with varied success. Such approaches to ecosystem-based disaster risk reduction appear to be most successful when local communities are closely involved as stakeholders throughout the process, and when careful attention is paid to the physical conditions of chosen sites to ensure that mangroves can thrive there.


Economic impact

The level of damage to the economy resulting from the tsunami depends on the scale examined. While the overall impact on the national economies was minor, local economies were devastated. The two main occupations affected by the tsunami were fishing and tourism. Some economists believe that damage to the affected national economies will be minor because losses in the tourism and fishing industries are a relatively small percentage of the GDP. However, others caution that damage to infrastructure is an overriding factor. In some areas drinking water supplies and farm fields may have been contaminated for years by saltwater from the ocean. The impact on coastal fishing communities and the people living there, some of the poorest in the region, has been devastating with high losses of income earners as well as boats and fishing gear. In Sri Lanka, artisanal fishery, in which the use of fish baskets, fishing traps, and spears are commonly used, is an important source of fish for local markets; industrial fishery is the major economic activity, providing direct employment to about 250,000 people. In recent years the fishery industry has emerged as a dynamic export-oriented sector, generating substantial foreign exchange earnings. Preliminary estimates indicated that 66% of the fishing fleet and industrial infrastructure in coastal regions were destroyed by the wave surges. While the tsunami destroyed many of the boats vital to Sri Lanka's fishing industry, it also created a demand for fibreglass-reinforced plastic catamarans in the boatyards of
Tamil Nadu Tamil Nadu (; , TN) is a state in southern India. It is the tenth largest Indian state by area and the sixth largest by population. Its capital and largest city is Chennai. Tamil Nadu is the home of the Tamil people, whose Tamil language ...
. Given that over 51,000 vessels were lost to the tsunami, the industry boomed. However, the huge demand has led to lower quality in the process, and some important materials were sacrificed to cut prices for those who were impoverished by the tsunami. Even though only coastal regions were directly affected by the waters of the tsunami, the indirect effects have spread to inland provinces as well. Since the media coverage of the event was so extensive, many tourists cancelled vacations and trips to that part of the world, even though their travel destinations may not have been affected. This ripple effect could especially be felt in the inland provinces of Thailand, such as Krabi, which acted as a starting point for many other tourist destinations in Thailand. Countries in the region appealed to tourists to return, pointing out that most tourist infrastructure is undamaged. However, tourists were reluctant to do so for psychological reasons. Even beach resorts in parts of Thailand which were untouched by the tsunami were hit by cancellations. Both the earthquake and the tsunami may have affected shipping in the
Malacca Straits The Strait of Malacca is a narrow stretch of water, 500 mi (800 km) long and from 40 to 155 mi (65–250 km) wide, between the Malay Peninsula (Peninsular Malaysia) to the northeast and the Indonesian island of Sumatra to the southwest, connec ...
, which separate Malaysia and the Indonesian island of Sumatra, by changing the depth of the seabed and by disturbing navigational buoys and old shipwrecks. In one area of the Strait, water depths were previously up to , and are now only in some areas, making shipping impossible and dangerous. These problems also made the delivery of relief aid more challenging. Compiling new navigational charts may take months or years. Officials also hoped that piracy in the region would drop off, since the tsunami had killed pirates and destroyed their boats. Due to multiple factors, there was a 71.6% drop in the number of piracy incidents between 2004 and 2005, from 60 to 17 incidents. Levels remained relatively low for some years. However, between 2013 and 2014, piracy incidents rose dramatically by 73.2% to exceed pre-tsunami levels.


Historical context

The last major tsunami in the Indian Ocean was about A.D. 1400. In 2008, a team of scientists working on Phra Thong, a barrier island along the hard-hit west coast of Thailand, reported evidence of at least three previous major tsunamis in the preceding 2,800 years, the most recent from about 700 years ago. A second team found similar evidence of previous tsunamis in Aceh, a province at the northern tip of Sumatra; radiocarbon dating of bark fragments in the soil below the second sand layer led the scientists to estimate that the most recent predecessor to the 2004 tsunami probably occurred between A.D. 1300 and 1450. The 2004 earthquake and tsunami combined is the world's deadliest natural disaster since the 1976 Tangshan earthquake. The earthquake was the third-most-powerful earthquake recorded since 1900. The deadliest-known earthquake in history occurred in 1556 in Shaanxi, China, with an estimated death toll of 830,000, though figures from this period may not be as reliable. Before 2004, the tsunami created in both Indian and Pacific Ocean waters by the 1883 eruption of
Krakatoa Krakatoa (), also transcribed (), is a caldera in the Sunda Strait between the islands of Java and Sumatra in the Indonesian province of Lampung. The caldera is part of a volcanic island group ( Krakatoa archipelago) comprising four islands. T ...
, thought to have resulted in anywhere from 36,000 to 120,000 deaths, had probably been the deadliest in the region. In 1782, about 40,000 people are thought to have been killed by a tsunami (or a cyclone) in the South China Sea. The deadliest tsunami before 2004 was Italy's
1908 Messina earthquake The 1908 Messina earthquake (also known as the 1908 Messina and Reggio earthquake) occurred on 28 December in Sicily and Calabria, southern Italy with a moment magnitude of 7.1 and a maximum Mercalli intensity of XI (''Extreme''). The epice ...
on the
Mediterranean Sea The Mediterranean Sea is a sea connected to the Atlantic Ocean, surrounded by the Mediterranean Basin and almost completely enclosed by land: on the north by Western and Southern Europe and Anatolia, on the south by North Africa, and on the ...
where the earthquake and tsunami killed about 123,000.


Other effects

Many health professionals and aid workers have reported widespread psychological trauma associated with the tsunami. Traditional beliefs in many of the affected regions state that a relative of the family must bury the body of the dead, and in many cases, no body remained to be buried. Women in Aceh required a special approach from foreign aid agencies, and continue to have unique needs. The hardest-hit area, Aceh, is a religiously conservative Islamic society and has had no tourism nor any Western presence in recent years due to the
insurgency An insurgency is a violent, armed rebellion against authority waged by small, lightly armed bands who practice guerrilla warfare from primarily rural base areas. The key descriptive feature of insurgency is its asymmetric nature: small irr ...
between the
Indonesian military , founded = as the ('People's Security Forces') , current_form = , disbanded = , branches = , headquarters = Cilangkap, Jakarta , website = , commander-in-chief = Joko Widodo , ...
and
Free Aceh Movement The Free Aceh Movement ( id, Gerakan Aceh Merdeka, GAM; ace, Geurakan Acèh Meurdèka / Gěrakan Aceh Měrdeka) was a separatist group seeking independence for the Aceh region of Sumatra, Indonesia. GAM fought against Indonesian government f ...
(GAM). Some believe that the tsunami was divine punishment for lay Muslims shirking their daily prayers or following a materialistic lifestyle. Others have said that Allah was angry that Muslims were killing each other in an ongoing conflict. Saudi cleric
Muhammad Al-Munajjid Muhammad Saalih Al-Munajjid (محمد صالح المنجد) (born June 7, 1960/30 Dhul hijjah,1380) is a Syrian-born Palestinian- Saudi Islamic scholar. He is the founder of the fatwa website IslamQA, a popular website for Saudi Arabian Salafi r ...
attributed it to divine retribution against non-Muslim vacationers "who used to sprawl all over the beaches and in pubs overflowing with wine" during Christmas break. The widespread devastation caused by the tsunami led GAM to declare a cease-fire on 28 December 2004 followed by the Indonesian government, and the two groups resumed long-stalled peace talks, which resulted in a peace agreement signed 15 August 2005. The agreement explicitly cites the tsunami as a justification. In a poll conducted in 27 countries, 15% of respondents named the tsunami the most significant event of the year. Only the Iraq War was named by as many respondents. The extensive international media coverage of the tsunami, and the role of mass media and journalists in reconstruction, were discussed by editors of newspapers and broadcast media in tsunami-affected areas, in special video-conferences set up by the Asia Pacific Journalism Centre. The tsunami left both the people and government of India in a state of heightened alert. On 30 December 2004, four days after the tsunami, Terra Research notified the India government that its sensors indicated there was a possibility of 7.9 to 8.1 magnitude tectonic shift in the next 12 hours between Sumatra and New Zealand. Press Trust of India (30 December 2004) "Alert scaled down, capping day long confusion." In response, the Indian
Minister of Home Affairs An interior minister (sometimes called a minister of internal affairs or minister of home affairs) is a cabinet official position that is responsible for internal affairs, such as public security, civil registration and identification, emergency ...
announced that a fresh onslaught of deadly tsunami was likely along the southern Indian coast and the Andaman and Nicobar Islands, even as there was no sign of turbulence in the region. The announcement generated panic in the Indian Ocean region and caused thousands to flee their homes, which resulted in jammed roads.Tran, Tina. (30 December 2004)
Associated Press The Associated Press (AP) is an American non-profit news agency headquartered in New York City. Founded in 1846, it operates as a cooperative, unincorporated association. It produces news reports that are distributed to its members, U.S. ne ...

False tsunami alarm sparks panic in Indian Ocean region.
"
The announcement was a false alarm, and the Home Affairs minister withdrew their announcement. On further investigation, the India government learned that the consulting company Terra Research was run from the home of a self-described earthquake forecaster who had no telephone listing and maintained a website where he sold copies of his detection system. The tsunami had a severe humanitarian and political impact in Sweden. The hardest-hit country outside Asia, Sweden, lost 543 tourists, mainly in Thailand. The Persson Cabinet was heavily criticized for its inaction.
Smith Dharmasaroja Smith Dharmasaroja ( th, สมิทธ ธรรมสโรช; ; 6 November 1937) is a Thai government official. In 1998, while serving as a meteorologist, he predicted that an earthquake and tsunami "is going to occur for sure."
, a meteorologist who had predicted that an earthquake and
tsunami A tsunami ( ; from ja, 津波, lit=harbour wave, ) is a series of waves in a water body caused by the displacement of a large volume of water, generally in an ocean or a large lake. Earthquakes, volcanic eruptions and other underwater exp ...
"is going to occur for sure" way back in 1994, was assigned the development of the Thai tsunami warning system. The Indian Ocean Tsunami warning system was formed in early 2005 to provide an early warning of tsunamis for inhabitants around the Indian Ocean coasts. The changes in the distribution of masses inside the Earth due to the earthquake had several consequences. It displaced the North Pole by . It also slightly changed the shape of the Earth, specifically by decreasing Earth's oblateness by about one part in 10 billion, consequentially increasing Earth's rotation a little and thus shortening the length of the day by 2.68 microseconds.


Humanitarian response

A great deal of humanitarian aid was needed because of widespread damage to the infrastructure, shortages of food and water, and economic damage. Epidemics were of particular concern due to the high population density and tropical climate of the affected areas. The main concern of humanitarian and government agencies was to provide sanitation facilities and fresh drinking water to contain the spread of diseases such as cholera, diphtheria,
dysentery Dysentery (UK pronunciation: , US: ), historically known as the bloody flux, is a type of gastroenteritis that results in bloody diarrhea. Other symptoms may include fever, abdominal pain, and a feeling of incomplete defecation. Complications ...
, typhoid and hepatitis A and . There was also a great concern that the death toll could increase as disease and hunger spread. However, because of the initial quick response, this was minimized. In the days following the tsunami, significant effort was spent in burying bodies hurriedly due to fear of disease spreading. However, the public health risks may have been exaggerated, and therefore this may not have been the best way to allocate resources. The
World Food Programme The World Food Programme; it, Programma alimentare mondiale; es, Programa Mundial de Alimentos; ar, برنامج الأغذية العالمي, translit=barnamaj al'aghdhiat alealami; russian: Всемирная продовольствен� ...
provided food aid to more than 1.3 million people affected by the tsunami. Nations all over the world provided over US$14 billion in aid for damaged regions, with the governments of Australia pledging US$819.9 million (including a US$760.6 million aid package for Indonesia), Germany offering US$660 million, Japan offering US$500 million, Canada offering US$343 million, Norway and the Netherlands offering both US$183 million, the United States offering US$35 million initially (increased to US$350 million), and the
World Bank The World Bank is an international financial institution that provides loans and grants to the governments of low- and middle-income countries for the purpose of pursuing capital projects. The World Bank is the collective name for the Inte ...
offering US$250 million. Also, Italy offered US$95 million, increased later to US$113 million of which US$42 million was donated by the population using the SMS system Four countries, Australia, India, Japan and the United States formed an ad-hoc corroborative group, and it was the origin of
Quadrilateral Security Dialogue The Quadrilateral Security Dialogue (QSD), commonly known as the Quad, is a strategic security dialogue between Australia, India, Japan and the United States that is maintained by talks between member countries. The dialogue was initiated in ...
. According to USAID, the US has pledged additional funds in long-term U.S. support to help the tsunami victims rebuild their lives. On 9 February 2005, President Bush asked Congress to increase the U.S. commitment to a total of US$950 million. Officials estimated that billions of dollars would be needed. Bush also asked his father, former President George H. W. Bush, and former President Bill Clinton to lead a U.S. effort to provide private aid to the tsunami victims. In mid-March, the
Asian Development Bank The Asian Development Bank (ADB) is a regional development bank established on 19 December 1966, which is headquartered in the Ortigas Center located in the city of Mandaluyong, Metro Manila, Philippines. The bank also maintains 31 field offic ...
reported that over US$4 billion in aid promised by governments was behind schedule. Sri Lanka reported that it had received no foreign government aid, while foreign individuals had been generous. Many charities were given considerable donations from the public. For example, in the United Kingdom, the public donated roughly £330 million sterling (nearly US$600 million). This considerably outweighed the allocation by the government to disaster relief and reconstruction of £75 million and came to an average of about £5.50 (US$10) donated by every citizen. In August 2006, fifteen local aid staff working on post-tsunami rebuilding were found executed in north-east Sri Lanka after heavy fighting between government troops and the Tamil Tiger rebels, the main umbrella body for aid agencies in the country said.


In popular culture


Film and television

* ''Children of Tsunami: No More Tears'' (2005), a 24-minute documentary * ''The Wave That Shook The World'' (2005), educational television-series documentary about the tsunami * '' Tsunami: The Aftermath'' (2006), a two-part television miniseries about its aftermath * ''
Hereafter The afterlife (also referred to as life after death) is a purported existence in which the essential part of an individual's identity or their stream of consciousness continues to live after the death of their physical body. The surviving ess ...
'' (2010), a main character's life is affected after surviving the tsunami while on vacation * '' Hafalan Shalat Delisa'' (2011), an Indonesian movie * '' The Impossible'' (2012), an English-language Spanish film based on the story of María Belón and her family * '' Kayal'' (2014), a Tamil drama film which culminates with the tsunami


Literature

* Paint the Sky with Stars, Selected Poetry in Remembrance of the Boxing Day Tsunami 2004 (2005) edited by
Stephen Robert Kuta Stephen Robert Kuta (ˈkʉːˌta) is a British author, poet, historian, and genealogist based in the UK. He has published several books and poetry anthologies. Published works He published selected prose and poetry in several anthologies in the ...
*''The Killing Sea'' (2006), two teenagers struggle to survive in the days after the tsunami *'' Wave'' (2013), a memoir by
Sonali Deraniyagala Sonali Deraniyagala (born 1964) is a Sri Lankan memoirist and economist. She currently serves as a lecturer in Economics at the SOAS South Asia Institute. She considers Joan Didion and Michael Ondaatje her favourite literary heroes. Personal lif ...


Music

* "12/26" by
Kimya Dawson Kimya Dawson (born November 17, 1972) is an American folk singer-songwriter, one half of the anti-folk duo the Moldy Peaches. Dawson's work with the Moldy Peaches earned them a cult following and critical acclaim, with their 2001 song "Anyone El ...
, about the event and the humanitarian efforts, from the perspective of a victim whose family died in the disaster


See also

*
Deaths in December 2004 The following is a list of notable deaths in December 2004. Entries for each day are listed alphabetically by surname. A typical entry lists information in the following sequence: * Name, age, country of citizenship at birth, subsequent country ...
– notable people killed in the 2004 Indian Ocean tsunami * List of earthquakes in 2004 * List of earthquakes in Indonesia * List of natural disasters by death toll *
Lists of earthquakes Earthquakes are caused by movements within the Earth's crust and uppermost mantle. They range from events too weak to be detectable except by sensitive instrumentation, to sudden and violent events lasting many minutes which have caused some of ...
* List of megathrust earthquakes


References


External links

*
The Sumatra-Andaman Islands Earthquake
nbsp;–
IRIS Consortium IRIS (Incorporated Research Institutions for Seismology) is a university research consortium dedicated to exploring the Earth's interior through the collection and distribution of seismographic data. IRIS programs contribute to scholarly research, ...

M9.1 Sumatra-Andaman Earthquake & Tsunami, 2004
nbsp;– Amateur Seismic Centre (ASC)

nbsp;– Zoriah Miller * * {{Authority control 2004 disasters in India Earthquakes in Sumatra 2004 earthquakes 2004 in India 2004 in Indonesia 2004 in Sri Lanka 2004 in the Maldives 2004 in Somalia 2004 in Thailand 2004 tsunamis Articles containing video clips December 2004 events in Asia History of Southeast Asia History of the Indian Ocean Megathrust earthquakes in India Megathrust earthquakes in Sumatra Natural disasters in India Natural disasters in Indonesia Natural disasters in Somalia Natural disasters in Sri Lanka Earthquakes in Thailand Earthquakes in Myanmar Tsunamis in India 2000s in Andhra Pradesh 2000s in Kerala 2000s in Tamil Nadu Tsunamis in Thailand Tsunamis in Myanmar